1. Field of the Invention
Embodiments of the present general inventive concept relate to an image forming apparatus having a charge device to charge a photoconductor.
2. Description of the Related Art
Generally, image forming apparatuses are devised to form an image on a printing medium according to input image signals. Examples of image forming apparatuses include printers, copiers, fax machines, and devices combining functions thereof.
An image forming apparatus may include, e.g., a body defining an external appearance of the image forming apparatus, a developing unit to attach developer to an electrostatic latent image to form a visible image, an exposure unit to form an electrostatic latent image on a charged photoconductor of the developing unit, a fusing unit to fuse developer transferred to a printing medium, a printing medium supply unit to supply a printing medium to a transfer device, and a printing medium discharge unit to discharge a printing medium, on which an image has been completely formed, to the outside of the body.
In operation of the image forming apparatus, after the exposure unit scans light to the charged photoconductor of the developing unit to form an electrostatic latent image on a surface of the photoconductor, developer is fed to develop the electrostatic latent image into a visible image. Subsequently, the transfer device transfers the visible image from the photoconductor to a printing medium supplied from the printing medium supply unit and the fusing unit fuses the transferred image to the printing medium to complete image formation on the printing medium. The resulting printing medium is discharged to the outside of the body by the printing medium discharge unit.
The developing unit includes a charge device to charge the photoconductor with a predetermined potential as described above. The charge device includes first and second electrodes spaced apart from each other to perform corona discharge therebetween, thereby serving to charge the photoconductor with a predetermined potential.
During corona discharge between the first electrode and the second electrode, byproducts of corona discharge, such as ozone, nitrogen oxide, nitrogen dioxide, etc., are generated in the charge device. Over time, these byproducts of corona discharge may oxidize or contaminate the electrodes, preventing the charge device from uniformly charging the surface of the photoconductor and resulting in image defects.